A crushing chamber is formed in gyratory and cone crushers between a fixed outer wear part and a movable inner wear part. Mineral material is crushed in the crushing chamber by moving the inner wear part radially through an excentric.
FIG. 1 shows a support cone 10 of a cone crusher, and an inner wear part 1 mounted onto the support cone is fixed by a fixing bolt 12. The fixing bolt 12 is covered by a cover 13. FIG. 2 shows a support cone 20 of a gyratory crusher and an inner wear part 1′ mounted onto the support cone. The inner wear part 1′ of the gyratory crusher is fixed onto the support cone 20 by a fixing nut 22 which is mounted on a shaft 23.
In FIGS. 1 and 2 the inner wear parts 1, 1′ are fixed on the support cones 10, 20 through a torch ring 14. The torch ring 14 is welded at top to the fixing bolt 12 and correspondingly to the fixing nut 22 and from bottom to the inner wear part 1, 1′. The wear part is then further tightened on the support cone at the beginning of the crushing. When the wear part is detached the torch ring 14 is usually oxygen cut so that the fixing bolt/nut can be unscrewed. In some cases free space is formed for the oxygen cutting in the support cone immediately behind the torch ring.
Nowadays the inner wear part i.e. a mantle is typically lifted in place on the support cone by making use of projections 24 formed on an outer surface of the wear part such as “hooks” casted in connection with the manufacturing. Usually these projections are worn off in a worn wear part wherein new lifting points must be welded to the outer surface of the wear part when the wear part is dismounted.
The welding of the new lifting points to the wear part causes extra work phases and safety risks because it is difficult to control the quality of the welding operator and the weld. Replacing of the spent wear part by the new one takes place usually on site for example at a quarry. The wear part is usually difficult weldable material such as manganese steel, and a suitable welding additive is not necessarily available. Reliable joining of a lifting bracket of steel to a dirty manganese steel is difficult in construction conditions.
Lifting tools which are fixable to outside lifting points intended to lifting of the wear part are generally not fully lockable to the wear part, wherein realization of work safety and work safety regulations cannot be guaranteed in all circumstances. Detaching of the lifting tool from the wear part can damage the crusher. Dropping of the wear part can cause serious personal injuries.
WO 2011/029133 shows a lifting device for an inner wear part. Projections extending from a body of the lifting device are coupled with ribs formed to an edge of an opening of a wear part. The lifting device is rotated in the opening wherein the projections locate under the ribs. The lifting device is locked by preventing a backwards rotation of the lifting device. A radial recess formed additionally to the edge of the opening of the wear part is problematic because mineral material and water can enter in between the wear part and a support cone. When a torch ring is oxygen cut, vaporizing water and splashes cause a work safety risk. The edge of the opening of the wear part can be damaged during the oxygen cutting wherein the lifting device does not necessarily couple safely to the wear part.
An object of the invention is to create a reliable and simple method to handle the inner wear part. An object of the invention is to create a reliably liftable inner wear part. An object of the invention is to enhance safety of a crusher particularly in connection with the handling of the inner wear part. A particular object of the invention is to reduce dangerous operations in connection with the lifting of the inner wear part. A particular object is to create an alternative lifting tool which is lockable to the inner wear part.